When packages are formed by winding a strand in a helix on a core, the length of strand between the supply and the package is not constant, because the distances from the supply to the ends of the package are greater than the distance to intermediate locations. This results in uneven tension in the strand on the package, which may produce undesirable changes in the physical properties of the strand such, for example, as yarn. When the core is a cone, this condition is exaggerated, because the peripheral speed of the core varies continuously from one end to the other even though the angular velocity is constant. This condition is even more serious in the winding of yarn produced by open-end spinning, in which yarn is spun at a fixed rate determined by the speed of the yarn withdrawal rolls.
In order to remedy this problem, tension compensators have been employed to store strand when the tension is low and to release it from storage when the tension is high. Many such compensators have two spaced pins mounted on a member rotatable about a fixed axis, the pins being parallel to and on opposite sides of the axis. The member is biased to rotate in a predetermined direction and the strand between the supply and the package is threaded over one pin and under the other in such a zig-zag manner that tension in the strand exerts a force on the pins tending to rotate the member in opposition to its bias. The bias is adjusted such that it overcomes the force of the strand on the pins when tension is low, thereby storing strand, and the bias is overcome by the force of the strand on the pins when tension is high, thereby releasing strand from storage.
In the past threading of the strand through the tension compensator was accomplished manually, which consumed a considerable amount of time, especially when starting-up winding machines on which large numbers of packages are formed.